If a customer has 10 units of the ESA700 series with Basic OneQA automation software, can this software be installed on all 10 laptops individually, and can all 10 engineers use it simultaneously?

Yes. Each technician can be invited to the Basic tenant and download OneQA. If the customer purchases 10 ESA700 series devices, they would have 10 licenses, allowing all 10 users to be active simultaneously.